1. Field of the Invention
The present invention relates to automobile interior components in which soft trim cover material overlays a substrate component such that join and/or french seams in the soft trim cover material are aligned in a precise and stable manner.
2. Background Art
Many automobile interior components are of a construction in which a soft trim cover material layer overlays a substrate component. Modern fabrication of such components require increased tolerance control and stability for both initial and quality over time. Temporal instability may result from stresses induced in the soft trim cover material by the stretching and folding that is used to cover the substrate with the soft trim.
FIG. 1 provides an illustration of a prior art construction in which a substrate (usually at least partially foamed) is covered with soft trim layer. In FIG. 1, automobile interior component 10 includes trim cover 12 covering foam substrate 14. First trim pattern 16 is sewn to second trim pattern 18 along join seam 20. Typically, selvage section 22 is sewn to first trim pattern 16 along decorative seam 24. Similarly, selvage section 26 is sewn to second trim pattern 18 along decorative seam 28. Example of a decorative seam used in such applications is a French seam. In this prior art construction selvage sections 22, 26 along with join seam 20 are positioned over step section 30 with edge 32 of selvage section 22 aligned with edge 34 of foam substrate 14 and edge 36 of selvage section 26 aligned with edge 38 of foam substrate 14. In some variations only one edge is present for alignment. Although the prior art construction of FIG. 1 has worked reasonably well, tolerance control is problematic for some components. Loss of tolerance in the components results from variations in cutting trim patterns 16, 18, variations from sewing join seam 20 and decorative seams 24, 28, and variations in positioning trim cover 12 over the foam substrate 14.
U.S. Pat. No. 5,635,264 (the '264 patent) discloses another prior art construction in which a trim cover is placed over a foam substrate with somewhat improved tolerance control. FIG. 2 provides an illustration of the construction of the '264 patent. In this construction automobile interior component 50 includes trim cover 52 covering foam substrate 54. First trim pattern 56 is sewn to second trim pattern 58 along join seam 60 with positioning strip 62 interposes between first trim pattern 56 and second trim pattern 58. Again, selvage section 64 is sewn to first trim pattern 56 along decorative seam 66. Similarly, selvage section 68 is sewn to second trim pattern 58 along decorative seam 70. In this prior art construction selvage sections 64, 68 along with join seam 60 are positioned over step section 72 with edge 74 of selvage section 64 aligned with edge 76 of foam substrate 54 and edge 78 of selvage section 68 aligned with edge 80 of foam substrate 54. Improved positioning is achieved by placement of bottom section 82 of positioning strip 62 into positioning trench 84. Typically, this placement is accomplished by a person holding top section 86 during positioning or with automated placement. After placement, top section 86 of positioning strip 62 is torn away. Although the method of the '264 patent works well, the exposed sections of positioning strip 82 are sometimes undesirable. Moreover, the discarded top section 86 leads to undesirable material waste.
Accordingly, there exists a need for automobile interior components with improved positioning of a trim cover over a substrate.